Although Mary Leakey made several of the most important archeological discoveries involving early humans, she was generally eclipsed by her famous husband and collaborator, the renowned paleontologist Louis Leakey. While Mary conducted the digs with meticulous scientific rigor and was the actual finder of the most important archeological evidence, it was Louis Leakey who interpreted and publicized their findings.

Mary Leakey began participating in archaeological digs in England at age 17. She never attended university, considering herself temperamentally unsuited for formal education. In 1934 she met Louis Leakey, and moved to Kenya with him in 1935, where they began a 30-year collaboration to uncover evidence of early hominids. They were married in 1936 and had three children, all of whom became involved in paleontology. Their son, Richard E. Leakey, is a famous wildlife conservationist and political reformer as well as a paleontologist.

In 1948, Mary found the first perfectly preserved skull of a hominoid, Proconsul africanus, an ape-like ancestor of humans. In 1959 she discovered a hominid fossil in Olduvai Gorge, Tanzania, dubbed Zinjanthropus, which was thought to be 1.7 million years old. (It is now believed to be an australopithecine.) Some thought the discovery might be the “missing link” between humans and apes, and the Leakeys became world famous.

Mary Leakey's most important discovery, however, took place in 1978, when her team uncovered the footprints of two hominids in Laetoli, Tanzania. The footprints, thought to be 3.5 million years old, indicated that humans began walking upright much earlier than scientists previously thought.